A Newsweek magazine article of Aug. 20, 1990 on repetitive strain injury notes that many computer operators are claiming that the design of their computers has led to physical injuries. Specifically, the article notes that "hours at the computers put continuous stress on the wrists, elbows and shoulders. Tendons in the arm become inflamed, squeezing the nerves; the result is numbness and pain. Without early diagnosis and treatment, these injuries can develop into serious lifelong disabilities and loss of ability to work."
Existing furniture for typists and computer users does not properly position the computer operator's body relative to the keyboard, and does not properly support the body in any given position. One function of the elbow is to position the hand in space. Thus, proper positioning of the elbow itself is essential to proper positioning of the hand. The elbow is typically supported by the armrest on a chair. However, the armrests on a typical office chair are completely useless to support the arms of someone working at a computer keyboard. The armrests are too far back and too low because the chair must be designed to fit under a table or desk, and because the occupant must be able to get into and out of the chair easily without serious interference from the armrests. The armrests do not properly support the weight of the arms. Thus, the trapezius muscle and other muscles of the neck and shoulder must support the full weight of the arms for prolonged periods of time, leading to chronic shoulder and neck pain, upper back problems, etc.
An armrest which is not properly padded will cause ulnar nerve problems. An armrest needs to provide broad support over a large contact area of the arm. It should also be adjustable to fit different users rather than be fixed in one location.